unidentified C++ exception when opening file twice in Overwrite mode about nixpy

[jgrewe]

This is a known bug (#78) and its on the list to-be-killed. Thanks for putting some weight on it!

The workaround is for the moment to set all objects you used to store blocks, data_arrays, files, etc explicitly to None before re-assigning values to it. The following code should work:

file = nix.File.open('foo.h5', nix.FileMode.Overwrite)
file = None
file = nix.File.open('foo.h5', nix.FileMode.Overwrite)

[cgars]

While risking to sound pretentious id like to point out that it might not be the same issue as \

nix_file = nix.File.open('foo.h5', nix.FileMode.ReadWrite)
nix_file = nix.File.open('foo.h5', nix.FileMode.ReadWrite)

does actually work.
I think it might just be that its not possible to overwrite and open h5 file. If this were the case then i think nixpy should simply sthrough a proper error.

[gicmo]

I am still not sure what exactly is going on in issue #78 but what is going on here is what @cgars already wrote (I think), i.e. that by the time you open the same file in overwrite mode (e.g. the right side of the statement) the file on the right is still open and therefore it doesn't work.

[stoewer]

The current version of nix/nixpy now behaves like this:

nix_file = nix.File.open('foo.h5', nix.FileMode.Overwrite)
nix_file = nix.File.open('foo.h5', nix.FileMode.Overwrite)

This throws a RuntimeError because an opened file is opened again with truncate mode. I think this is the correct behavior. Reopen a file with other open modes works, which is also OK.

To reopen a file with truncate mode it has to be closed properly. This can be done with close, or by assigning None:

file = nix.File.open('foo.h5', nix.FileMode.Overwrite)
file = None
file = nix.File.open('foo.h5', nix.FileMode.Overwrite)

file = nix.File.open('foo.h5', nix.FileMode.Overwrite)
file.close()
file = nix.File.open('foo.h5', nix.FileMode.Overwrite)

Therefore I suggest to close this issue as well as #78.

[jgrewe]

I cross-checked and agree to close this issue.